Technical Field
The present invention relates to a substrate holding inspection method in which it is inspected whether or not a substrate is properly held by a substrate holding unit in a case where the substrate is fixed and is rotary processed by a semiconductor manufacturing system and the like, and to a substrate processing system that performs substrate processing by using the substrate holding inspection method. More specifically, the present invention relates to an automatic determination method of an inspection region of substrate holding state abnormality inspection.
Related Art
In a semiconductor manufacturing system and the like, as a technique for performing various processing such as cleaning and coating on a semiconductor substrate such as a wafer (hereinafter, simply referred to as the substrate), there is a substrate processing system that performs the processing by holding the substrate in a substantially horizontal attitude by a substrate holding member and by supplying process liquid while rotating the substrate. To enable high-speed rotation of the substrate, such substrate processing system has a plurality of substrate holding members on a circumference corresponding to an outer peripheral shape of a substrate W at an appropriate interval as illustrated in FIG. 16. The substrate holding members include a fixing holding member 101 for holding the substrate in a fixed state, and an opening and closing holding member 102 for opening and closing when attaching and detaching the substrate W to and from the system.
The fixing holding member 101 includes a fixed shaft 101a fixed to a base 103, and a fixed piece 101b fixed to the fixed shaft 101a, having a drum shape, and supporting a peripheral portion of the substrate W with a recessed portion on a lateral face thereof. The opening and closing holding member 102 includes a rotation shaft 102a fixed to the base 103, and an opening and closing piece 102b having a drum shape with a notch portion 102c formed in a part thereof and being eccentrically and rotatably fixed to the rotation shaft 102a. 
Then, to attach and detach the substrate W to and from the system, the opening and closing piece 102b is rotated on the rotation shaft 102a, the opening and closing piece 102b is moved in a direction away from the substrate W, and the notch portion 102c is faced to the substrate W, whereby abutting of the substrate holding members on the peripheral portion of the substrate W is released. On the other hand, to fix the substrate W to the system, the opening and closing piece 102b is rotated on the rotation shaft 102a, the opening and closing piece 102b is moved in a direction approaching the substrate W, and the notch portion 102c is moved to a position not facing the substrate W. Accordingly, all of the substrate holding members abut on the peripheral portion of the substrate W, whereby the substrate W is sandwiched thereby and held in the horizontal attitude.
However, due to a reason that the substrate W rides on a slant face of the recessed portion of the opening and closing piece 102b or the fixed piece 101b and the like, holding of the substrate W by the substrate holding members may be incomplete, or the substrate W may be held in a tilted state against a rotation axis thereof. Starting the processing of the substrate W in such state may cause a problem in that, due to rotation thereof, the substrate W may drop off from the substrate holding member and be damaged or the system itself may be damaged. To avoid such problem, there have been proposed an inspection system and an inspection method with which a position is inspected by imaging at least an outer peripheral portion of a disk-shaped object to be measured placed on a rotary table by a camera, by processing an image signal that has been imaged, and by comparing image information with standard image information stored in advance in a storage unit (see, for example, JP H10-321705 A).
As such system, there is also a system that inspects a holding state of the substrate by detecting a change in density (or brightness, the same for the “density” hereinafter) in a part of a region of a photographed image after a rotation start of the substrate W and the substrate holding member. An exemplary photographed image in this case is illustrated in FIG. 17. In FIG. 17, there are defined a rotation start determination region 121 for determining the rotation start of the substrate W and the substrate holding member with high sensitivity, and a chuck abnormality determination region 122 for determining abnormality of the holding state of the substrate with high sensitivity. Particularly from a density change in the rotation start determination region 121 and the chuck abnormality determination region 122, the rotation start of the substrate W and the substrate holding member and abnormality of the holding state of the substrate W are detected.
Here, the above-described rotation start determination region 121 and the chuck abnormality determination region 122 as well as a threshold for determining each of the regions are often set by an engineer who is present at a time of delivering the system. The engineer, however, may not always have detailed knowledge of image processing and camera adjustment/optical adjustment, whereby it is sometimes difficult to appropriately set the rotation start determination region 121 and the chuck abnormality determination region 122 as well as the threshold for determining each of the regions. Furthermore, in a case where a position of the camera for photographing an image of the substrate W and the substrate holding member is changed after the system is started to be used, it is necessary to reset the rotation start determination region 121 and the chuck abnormality determination region 122 as well as the threshold for determining each of the regions, and in such case, a user needs to take an action each time to perform resetting by himself, to request for an engineer having expertise to be dispatched, or the like, whereby it has been imposing a heavy workload on the user.